The invention relates to an x-ray diagnostic installation for x-ray photographs comprising a program control device for the photographic cycle which contains an electronic read-only memory for each photographic program, whose input is connected to a resettable pulse counter which is actuatable step-by-step via a clock pulse generator and which memory delivers program signals predetermined by its program that correspond to the output signals of the pulse counter, and wherein the outputs of all read-only memories are connected to the component parts they control via a program selector.
In an x-ray diagnostic installation of this type (U.S. Ser. No. 791,060 filed Apr. 26, 1977), the program storage and program control during a photographic cycle ensue purely electronically. Therefore, the scanning of mechanical recording carriers, e.g. data cards (U.S. Pat. No. 3,999,044), is not necessary and the operational dependability is very high. The program selection can take place in a simple manner by means of keys. Because of the use of electronic read-only memories, it is possible to conduct a program trial run, wherein for example the values and magnitudes respectively predetermined are optically indicated.
In an x-ray diagnostic installation of the type cited, there is often a desire to alter, i.e. to correct, individual program steps of a fixed program. In a further development of the subject matter of the parent application, there exists indeed the possibility of freely programming a photographic program by means of a freely programmable memory. In many cases, however, the physician does not desire to make up an entirely new program, but rather to alter only a few or even only one program step of a fixed program.